This invention relates to transfer molding of synthetic resins, and more particularly to a novel electrically driven plunger mechanism for multi-plunger transfer molding presses.
The plunger mechanism for transfer molding presses heretofore has included an extensible fluid pressure piston-cylinder unit for each plunger, supplied with fluid pressure from a common source. This not only incurs the high cost of hydraulic power equipment and the plant space for it, it also imposes serious limitations on the control of plunger velocity and pressure, creates a noisy environment containing hydraulic fluid fumes and requires lubrication with consequent discharge of oil vapor. In multiple plunger systems utilizing either fluid pressure or electrical power for driving the plungers, no one has provided individual control of plunger velocity and pressure.